XMonad.Util.TreeZipper

Zipper over the Data.Tree data structure. This module is based on rosezipper.

Data structure

data TreeZipper a

A Zipper over the Data.Tree data structure.

Very crappy visualization of the TreeZipper data structure

             (tz_parents)
       ([*],       *, [*])
       ([*, *],    *, [])
       ([],        *                  [*,   *])
                   |                   |    |
  +-------+--------+-------+------+  +-*-+  *
  |       |        |       |      |  |   |
 (tz_before) (tz_current) (tz_after) *   *
  |       |                |      |
+-*-+     *                *      *
|   |
*   *

Constructors

TreeZipper

Fields

• tz_current :: Tree a

  the currently focused sub-tree under the cursor

• tz_before :: Forest a

  all sub-tree's to the left of the cursor that have the same parent

• tz_after :: Forest a

  all sub-tree's to the right of the cursor that have the same parent

• tz_parents :: [(Forest a, a, Forest a)]

  list zippers for each parent level, the first element is the current parent

cursor :: TreeZipper a -> a

Get the highlighted value

Conversion

fromForest :: Forest a -> TreeZipper a

Create a TreeZipper from a list of Trees focused on the first element

toForest :: TreeZipper a -> Forest a

Convert the entire zipper back to a Forest

getSubForest :: TreeZipper a -> Forest a

Create a Forest from all the children of the current parent

Navigation

rootNode :: TreeZipper a -> TreeZipper a

Go to the upper most node such that nothing is before nor above the cursor

parent :: TreeZipper a -> Maybe (TreeZipper a)

Move to the parent node

children :: TreeZipper a -> Maybe (TreeZipper a)

Move the cursor one level down to the first node

nextChild :: TreeZipper a -> Maybe (TreeZipper a)

Go to the next child node

previousChild :: TreeZipper a -> Maybe (TreeZipper a)

Go to the previous child node

Utils

nodeDepth :: TreeZipper a -> Int

How many nodes are above this one?

nodeIndex :: TreeZipper a -> Int

How many nodes are before the cursor? (on the current level)

followPath :: Eq b => (a -> b) -> [b] -> TreeZipper a -> Maybe (TreeZipper a)

follow a Path specified by the list of nodes

findChild :: (a -> Bool) -> TreeZipper a -> Maybe (TreeZipper a)

go to the first node next to the cursor that matches

isLeaf :: TreeZipper a -> Bool

Check whenther this is a leaf node

isRoot :: TreeZipper a -> Bool

Check whenther this is a leaf node

isLast :: TreeZipper a -> Bool

Check whenther this the last child

isFirst :: TreeZipper a -> Bool

Check whenther this the first child